Semiconductor devices are used extensively in various devices throughout the electronics industry and the world. Semiconductor devices, also known as chips, are fabricated on a substrate that includes hundreds or even thousands of chips. In today's semiconductor manufacturing industry, there is a constant push to increase substrate sizes and decrease feature sizes of the semiconductor devices formed on the substrates. It is critically important to control the uniformity of each processing operation across the substrate. Stated alternatively, it is important that each processing operation is carried out uniformly throughout the entire substrate. It is even more challenging to control uniformity to the required levels as substrate sizes increase and feature sizes decrease.
Non-uniformities do occur in the real world of semiconductor manufacturing, however. Various factors may contribute to the non-uniformities. The non-uniformities may be attributable to various processing operations. Advanced measurement techniques and advanced morphology and analytical equipment enable these non-uniformities to be determined. The non-uniformities may manifest themselves in different film thicknesses across a substrate, in a variation in critical dimension (CD) measurements across a substrate or in various other ways. The non-uniformities can result in hundreds or thousands of non-functional chips on a substrate.
The fabrication of semiconductor devices is a cost-intensive process and it would therefore be desirable to apply advanced process control techniques to compensate for non-uniformities across a substrate and produce functional chips throughout the substrate.